The present invention relates to self-locking pin devices. The invention is particularly useful for internally fixing bone fractures, and is therefore described below with respect to this application, but it will be appreciated that the invention could advantageously be used in other applications as well.
Fractures of the phalanges (i.e., the bones in the fingers and toes) are one of the most common encountered in the human skeleton. Many of these fractures and those of other small bones, and small bone fragments, must be treated by internal fixation methods in order to achieve good anatomical position, early mobilization, and fast and complete rehabilitation of the injured patient. The internal fixation techniques commonly followed today use Kirschner wires (K-wires), intermeduallary pins, wirings, plates, or screws, and combinations of the foregoing, the object being to reach the best anatomical and functional condition of the traumatized bone in the simplest operative procedure and with a minimal use of foreign implanted stabilizing material.
A fixation of the fractured line by a single K-wire is usually the least harmful and the easiest to execute. However, a single K-wire stabilizes only a single spacial plane of movement, whereas the forces acting on the fractured bone are usually in more than one plane; therefore this technique is impractical in most cases. Probably the most common procedure is to use two crossed K-wires transcutaneously or through an explorative incision, but this is a rather extensive procedure and produces a relatively large mass of foreign implanted material. Other internal fixation methods involve even more extensive procedures, with a greater iatrogenic trauma to the injury, and with a larger mass of foreign implanted material, in order to produce a three-place stabilization of the fractured bone.